Math Review

Matrix Calculus

time derivative vs. gradient
http://en.wikipedia.org/wiki/Matrix_calculus

Derivative Matrix

http://mathinsight.org/derivative_matrix
http://mathinsight.org/derivative_multivariable_examples

Gradient

http://mathinsight.org/gradient_vector

Multivariable Taylor Series

http://mathinsight.org/taylors_theorem_multivariable_introduction
http://mathinsight.org/taylor_polynomial_multivariable_examples